Antoine Pitrou <pit...@free.fr> added the comment: > Why pre-calculate everything? In the most common case any single > module will be imported once, if at all. And once it is imported it > will get cached in sys.modules, alleviating the need to hit the finder > again. So from a performance standpoint wouldn't it be better not to > do all of the pre-calculation and instead do that as needed assuming > that sys.modules will shield the finder from having to do repetitive > things like figuring out what loader is needed?
I figured it would avoid repetitive tests for all 10 suffixes. That said, I have now tried the alternative: find_module() is around 50% slower, but building the cache is 10x faster. Perhaps this is a winner. It would depend on the situation (short or long sys.path, few or many imports, etc.). Perhaps you can try both patches on your bootstrap repo? > Plus if the finder gets its cache invalidated frequently it will > simply be wasting its time. Well, in real-world situations I don't think the cache will ever get invalidated: because imports are mostly done at startup, and because invalidating the cache means you are installing new libraries or updating existing ones while a running program is about to import something. > Otherwise it's good to know three of us now have independently come up > with fundamentally the same idea for speeding up imports. =) Yup :) ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue14043> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
